Kombinierte CO 2 ‐Laser‐ und photodynamische Therapie erhöht die Wirksamkeit der Behandlung von Basalzellkarzinomen

Known and new facts on basal cell carcinoma

Basal cell carcinoma (BCC) is the most common malignant tumor in light‐skinned people and amounts to about 75 % of all cases of skin cancer. Increasing incidence rates have been reported for decades all over the world. The main risk factors include UV radiation, male sex, light skin type, advanced age, long‐term immunosuppression, a positive individual or family history, and certain genodermatoses. BCC metastasizes only rarely, and its mortality is low, but it is associated with significant morbidity. Genetic mutations especially in the hedgehog pathway play an important role in BCC pathogenesis. Non‐invasive procedures such as optical coherence tomography or confocal laser scan microscopy are increasingly utilized for diagnostics in addition to visual inspection and dermatoscopy, but only in exceptional cases can histological confirmation of the diagnosis be dispensed with. Various clinical and histological subtypes have been defined. Differentiating between BCC with high and low risk of recurrence has a significant influence on the choice of treatment. Most BCC can be treated effectively and safely with standard surgery, or in selected cases with topical treatment. Locally advanced and metastasized BCC must be treated with radiation or systemic therapy. Radiation is also an option for older patients with contraindications for surgery. The hedgehog inhibitors vismodegib and sonidegib are currently approved for systemic therapy of BCC in Europe. Approval for the PD1 inhibitor cemiplimab as second‐line therapy is expected in the near future.

Topical Delivery of Nivolumab, a Therapeutic Antibody, by Fractional Laser and Pneumatic Injection

BACKGROUND AND OBJECTIVES

PD-L1 is a tumor ligand that binds to the PD-1 receptor on immune cells, thereby inhibiting the antitumor immune response. The antibody nivolumab is a PD-1 inhibitor, Food and Drug Administration approved for systemic treatment of several aggressive cancer types. Topically applied nivolumab may hold potential as a future strategy to treat keratinocyte cancer, but its molecular properties preclude unassisted topical uptake. The aim of this study was to investigate uptake and biodistribution of topically delivered nivolumab, assisted by two physical enhancement techniques with different delivery kinetics; ablative fractional laser (AFL) and electronically controlled pneumatic injection (EPI).

STUDY DESIGN/MATERIALS AND METHODS

In vitro porcine skin was exposed to CO₂ AFL (20 mJ/mb, 5% density), followed by passive diffusion of nivolumab in a Franz cell (1 mg/ml, 18 hours, n = 6) or treated with EPI (4 bar) for immediate delivery of nivolumab (1 mg/ml, 10 minutes, n = 6). The resulting nivolumab skin concentrations were quantified by enzyme-linked immunosorbent assay (ELISA) at three skin depths (100, 500, and 1500 µm), comparing the uptake from assisted delivery with intact skin. Biodistribution of nivolumab in the skin for all interventions was visualized by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) and fluorescence microscopy.

RESULTS

Delivery of nivolumab by AFL-assisted passive diffusion and immediate EPI both resulted in significantly enhanced uptake of nivolumab in all skin depths compared with intact skin (P < 0.05). With AFL, nivolumab concentrations reached 86.3 µg/cm³ (100 µm), 105.8 µg/cm³ (500 µm), and 19.3 µg/cm³ (1500 µm), corresponding to 2-10% of the applied concentration, with the highest deposition in the mid dermis. Immediate EPI delivered 429.4 µg/cm³ (100 µm), 584.9 µg/cm³ (500 µm), and 295.9 µg/cm³ (1500 µm) into the skin, corresponding to 29-58% of the applied nivolumab concentration. From qualitative visualization of the biodistribution, it appeared that nivolumab distributed in a horizontal and continuous homogenous band in the upper and mid dermis through AFL-exposed skin, whereas EPI-delivery showed a deep focal deposition extending into the deep dermis.

CONCLUSIONS

AFL-assisted passive diffusion and immediate EPI-assisted delivery show the potential to deliver therapeutic antibodies locally. Future in vivo and pharmacokinetic studies would reveal the full potential for topical antibody delivery by energy-based devices. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.